Timetable June 2009 beginning of the study May 2010 deadline for patients' entry and allocation August 2010 deadline for data collection of baseline and crown insertion measurements September 2010 deadline for data collection of 1-month follow up measurements February 2011 deadline for data collection of 6-month follow up measurements August 2011 deadline for data collection of 12-month follow up measurements August 2012 deadline for data collection of 24-month follow up measurements August 2013 deadline for data collection of 36-month follow up measurements August 2014 deadline for data collection of 48th month follow up measurements August 2015 deadline for data collection of 60th month follow up measurements February 2016 deadline for final publication of data